Embodiments provide methods and structures for purification or volume reduction of a brine by an advanced vacuum distillation process (AVMD) to achieve higher flux by passage of vapors through an AVMD distillation unit. In one example, brine is circulated in a tank. The tank may include one or more membrane pouches that are submerged in the circulating brine or placed above the water level of the hot circulating brine. In other embodiments the membrane pouches are outside of the tank that includes the hot circulating brine but still in communication with it. The circulating brine is heated, allowing creation of water vapor. Using a vacuum, the water vapor is drawn through the membrane, where it may be condensed and subjected to further beneficial use. This process can concentrate to levels to generate crystals or solids, which can be separated and utilized.